Yuval Diskin, the former head of the Shin Bet, launched an unprecedentedly harsh assault on Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak on Friday, saying they acted out of “messianistic” impulses, were misleading the public over the Iranian challenge, and that he had no faith in their capacity to launch a war on Iran or extricate Israel from one.

Speaking at the Majdi Forum in Kfar Saba, a Tel Aviv suburb, Diskin said there might be “a measure of truth” in the first component of the Netanyahu-Barak assertions that “if Israel doesn’t act, the Iranians will get the bomb.” But there was no truth in the second component they were peddling — that “if Israel does act, the Iranians won’t get the bomb.” He said the two politicians were appealing to “the idiots within the Israeli public” in making that claim.

Diskin, who stepped down as Shin Bet chief after six years last year, and who has never previously spoken out publicly in this way, said Netanyahu and Barak were not fit to lead Israel. “I don’t have confidence” in either of them, he said. This was not the leadership that was needed if Israel was to embark on an attack on Iran, not the leadership capable of stewarding a possible regional war.

He cited experts who had long argued, credibly he said, that an Israeli attack on Iran would simply enable the regime there to speed to the bomb openly, with a perceived increased sense of legitimacy.

Diskin’s critique outstrips in its ferocity and personal nature even the repeated public assaults on government thinking regarding Iran that have been launched in recent months by the head of the other intelligence agency who served in parallel with him, ex-Mossad chief Meir Dagan. Dagan has blasted as “stupid” the notion that an Israeli attack on Iran should be contemplated in the near future.

Netanyahu and Barak, by contrast, have in recent months indicated that sanctions on Iran are not working, and that the moment of truth on possible military intervention is only months away.

The fact that both the long-serving ex-intelligence chiefs who have worked with the current coalition are now so publicly and stridently denouncing the thinking of the top political leadership gives added significance to the onslaught. Both were involved until recently in compiling and assessing the most sensitive information; both worked extremely closely with the leaders Diskin so personally attacked on Friday.

Diskin also derided Barak’s assessment that Bashar Assad would soon lose power in Syria, saying that the Assad regime would survive unless there was western intervention.

He also called for an interim agreement with the Palestinians, even though no “end of conflict” accord was feasible. If Israel did not wake up to the imperative for such an accord, Mahmoud Abbas would be gone, and the situation would be far more complex.

Diskin also warned of dozens of Jewish extremists, in the territories and inside Israel, who were capable of picking up weapons against other Jews, and said there could even be a repeat of the assassination of a prime minister, as befell Yitzhak Rabin in 1995.